In a typical cellular radio communication system (wireless communication system), an area is divided geographically into a number of cell sites, each defined by a radio frequency (RF) radiation pattern from a respective base transceiver station (BTS) antenna. The base station antennas in the cells are in turn coupled to a base station controller (BSC), which is then coupled to a telecommunications switch or gateway, such as a mobile switching center (MSC) and/or a packet data serving node (PDSN) for instance. The switch or gateway may then be coupled with a transport network, such as the PSTN or a packet-switched network (e.g., the Internet).
When an access terminal (such as a cellular telephone, pager, or appropriately equipped portable computer, for instance) is positioned in a cell, the access terminal communicates via an RF air interface with the BTS antenna of the cell. As the demand for wireless communications has grown, the volume of call traffic in most cell sites has correspondingly increased. To help manage the call traffic, most cells in a wireless network are usually further divided geographically into a number of sectors, each defined respectively by radiation patterns from directional antenna components of the respective BTS, or by respective BTS antennas. These sectors can be referred to as “physical sectors,” since they are physical areas of a cell site. Therefore, at any given instant, an access terminal in a wireless network will typically be positioned in a given physical sector and will be able to communicate with the transport network via the BTS serving that physical sector.
Consequently, when an access terminal connects to a transport network via a BTS, a communication path is typically established between the access terminal and the transport network via the air interface, the BTS, the BSC and the switch or gateway. Functioning collectively to provide wireless (i.e., RF) access services and transport in a wireless communication system, the BTS, BSC, MSC, and PDSN, comprise (possibly with additional components) what is generally referred to as a radio access network (RAN).
In a RAN that implements a code division multiple access (CDMA) coding scheme for air-interface communications, one or more “traffic channels” may be provided for communications between access terminals and the RAN. Further, one or more “control channels” may be provided by the RAN to send control and/or paging messages to access terminals.